WO2005018712A2

WO2005018712A2 - Dialysis catheter with stiffner

Info

Publication number: WO2005018712A2
Application number: PCT/US2004/027203
Authority: WO
Inventors: Chanaka Amarasinghe; James Bates
Original assignee: Datascope Investment Corp.
Priority date: 2003-08-20
Filing date: 2004-08-20
Publication date: 2005-03-03
Also published as: US20060189922A1; EP1663342A2; JP2007502678A; WO2005018712A3; EP1663342A4

Abstract

A double lumen continuous flow dialysis needle (1) and cannula (20) having a contiguous lumens (2, 3) of different lengths, the shorter lumen acting as blood intake lumen and the longer as the blood return lumen, each lumen (2, 3) having a beveled edge (4, 5) sloping outwardly and away from the needle (1) which can be inserted percutaneously and which minimizes the possibility of mixing cleansed blood with blood entering the intake lumen.

Description

TITLE: DIALYSIS CATHETER WITH STIFFNER

INVENTORS: Chanaka Amarasinghe James Bates DOC. NO: Data 93 RELATED APPLICATIONS

(0001) This application incorporates by reference and claims priority to provisiona application no. 60/496,419, filed on August 20, 2003.

BACKGROUND OF THE INVENTION (0002) This invention relates to a catheter primarily for use in dialysis and more specifically, to a dialysis catheter having a double lumen and a temporary stiffner.

(0003) Dialysis is currently performed in two basic ways. First, the conventional way employing two needles, one for removing the blood from the vein or body for processing in a dialysis machine and the other needle for returning processed blood back into the vein or body. In this conventional technique for dialysis, the two needles must be spaced apart a sufficient distance so as to prevent the cleansed blood from re-entering the blood outlet needle and returning to the dialysis machine but must be sufficiently close to each other to prevent the vein from collapsing.

(0004) A second known manner of performing dialysis utilizes a single needle in which blood is both extracted and returned through the same needle. However, single needle dialysis requires an intermittent occlusion machine which is capable of the cyclical operation necessitated by the single lumen needle with bi-directional flow. In addition, single needle dialysis can only operate within limited flow rates and accordingly is not suitable for all patients.

(0005) For repeated dialysis requirements, a method utilizing two long tubes of unequal length attached side by side is also known. In such a method the tubes are introduced into the femoral vein after surgery and remain there for several days during which hemodialysis is performed intermittently.

(0006) Also known in the art as shown in U.S. Patent 4,134,402 is to provide a double lumen catheter for dialysis capable of achieving blood flow rates comparable to the conventional two needle system while requiring only one puncture.

(0007) Further known in the art are multiple lumen catheters capable of use with a conventional dialysis machine as disclosed in U.S. Patents 5,221,255; 5,221,256 and 5,486,159.

(0008) Yet another object of the present invention is to provide a double lumen kink resistant catheter which can be easily inserted percutaneously for treatment and easily removed after each dialysis treatment.

(0009) Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the attached drawings.

SUMMARY OF THE INVENTION

(0010) Briefly stated, the present invention consists of a single catheter having two contiguous lumens or conduits, one slightly longer than the other. The needle is generally inserted into the vein or body at a slight angle to and in the direction of blood flow. The shorter lumen then serves as a blood intake lumen and the longer lumen, the end of which is positioned away from the end of the shorter lumen in the direction of blood flow, serves as a blood return lumen. With this arrangement, cleansed blood returning to the vein or fistula will not re-enter the intake lumen but will be carried "downstream".

BRIEF DESCRIPTION OF THE DRAWINGS

(0011) FIG. 1 is an illustration of the double lumen catheter of the present invention; (0012) FIG. 2 is a cross section of the double lumen catheter of the present invention;

(0013) FIG. 3 is an illustration of the front section of the double lumen catheter of the present invention;

(0014) FIG. 4 is an illustration of the rear section of the double lumen catheter of the present invention;

(0015) FIG. 5 is an illustration of another embodiment of the front section of the double lumen catheter of the present invention;

(0016) FIG. 6 is an illustration of a further embodiment of the front section of the double lumen catheter of the present invention is a flexible double lumen catheter according to the present invention;

(0017) FIG. 7 is an illustration of still another embodiment of the front section of the double lumen catheter of the present invention;

(0018) FIG. 8 is an illustration of another embodiment of the tip section of the double lumen catheter of the present invention;

(0019) FIG. 9 is an illustration of still another embodiment of the tip section of the double lumen catheter of the present invention; and

(0020) FIG 10 is a schematic showing blood flow during dialysis.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(0021) Referring to FIG. 1 it can be seen that the present invention consists of a single catheter 1 having lumens 2 and 3. The term "catheter" as used in this specification includes rigid metal devices such as needles as well as flexible plastic devices such as a cannula. As illustrated in FIGS. 1, 3, 5 and 7 the end of lumen 3 extends beyond the end of lumen 2 a sufficient distance to prevent mixing of the blood during the hemodialysis operation. The precise distance by which lumen 3 extends beyond lumen 2 is determined by the rate of blood flow, the angle of entrance of the double lumen , and the size of the vein or vessel in which the blood is flowing. Strictly by way of example, for an average vessel, (i.e., a surgically constructed blood vessel with rapid blood flow rates) having a diameter of 1/2 inch and processing blood at approximately 500 cubic centimeters per minute, the separation "d" FIG.2 would be approximately 1/4 inch. This separation could be as large as 3/4 inch under appropriate conditions.

(0022) In the preferred embodiment each lumen maybe provided with beveled edges at 4 and 5 sloping outwardly and away from the needle to promote insertion of the needle. It is preferable for return lumen 3 to be of semi-circular cross section near its end, FIGS. 1, 2 and 9. In the region where they are contiguous, the lumens define a compact cross section (FIG. 3). Lumen 2 preferably defines a semi-circular or circular cross section along its entire length.

(0023) Referring to FIG.2, it can be seen that in the region where the lumens are contiguous the lumens are separated by a wall 6. This wall 6 can be relatively thin construction inasmuch as its only function is to separate the blood return conduit 8 from the blood intake conduit 9. The wall 7, in contrast, must serve as a supporting wall and accordingly may be of heavier construction.

(0024) Turning now to FIG. 10, the actual operation will be described with reference to a double lumen needle constructed in accordance with the present invention. The double lumen needle 1 is inserted into the vein or body 10 at a slight angle in the direction of blood flow. The noninserted ends of the lumens are connected to a dialysis machine 11. This connection can be accomplished by separating the lumens 1, 2 into two noncontiguous polyethylene stabilizer tubes 12, 13 (FIG. 1) of circular cross section with standard luer ends so that conventional coupling members may be utilized. With the machine 11 is in operation, blood flows from the vein or body into lumen 2 via outwardly sloping beveled edge 4 to the dialysis machine 11 where blood is processed. The blood is then returned to the vein or body through lumen 3 at a sufficient pressure to overcome the natural resistance to the returning blood. Referring to FIG.4 it can be seen that the returning blood enters the vein or body at a point displaced some distance away from the point where blood enters intake lumen 2 does so via outwardly sloping beveled 4 and in the direction of blood flow in the vein or body. The blood flow through the body or vein then carries this processed blood away from re-entering intake lumen 2.

(0025) In order to aid in inserting, usually by the Seldinger technique, the catheter, especially if

Claims

flexible, a stiffner 20, see FIG 1. may be used, in order to prevent kinking. Once positioned, however, a retaining 14 is provided and the stiffner 20 is removed prior to operation of the machine 11.(0026) Lumens 13 and 14 are provided with standard hardware such as shown in FIGS. 1, 4 and 10. The use of this hardware being known in the art.(0027) From the foregoing, the present invention has been sufficiently described to enable others skilled in the art, by applying current knowledge, to adapt the same for varying conditions of use without departing from the essential items of novelty involved, which are intended to be defined and secured by claims to this application. Some of those varying conditions being shown in the additional embodiment of the invention as shown in FIGS. 5, 6, 7, 8 and 9.We claim:

1. A double lumen dialysis catheter, comprising a unitary straight, an internal divider extending along a longitudinal portion of said tube and forming said tube into a blood intake lumen and a blood return lumen, one end of said blood return lumen extending beyond the associated end of said blood inlet lumen a distance sufficient to prevent mixing of the returned blood with the blood taken in, the distal end of said blood inlet lumen terminating rearward of the juncture of the blood return lumen bevel and the associated lumen periphery each of said lumens defining blood flow paths parallel one to the other along the entire length thereof and at the ends thereof such that blood entering said intake lumen and blood leaving said return lumen enter and exit the associated blood vessel in a direction substantially parallel to the vessel wall.

2. A lumen flow dialysis device and cannula having lumens of different lengths, one lumen acting as blood intake lumen and the other as a blood return lumen, at least one lumen having a edge sloping outwardly and away from the dialysis portion which may be inserted percutaneously and which minimizes the possibility of mixing cleansed blood with blood entering the intake lumen.

3. A double lumen continuous flow dialysis needle and cannula having contiguous lumens of different lengths, one for blood intake and the other for blood return, each lumen having a beveled edge sloping outwardly and away from the needle to minimizes the possibility of mixing cleansed blood with blood entering the intake lumen.

4. A double lumen continuous flow dialysis needle and cannula having contiguous lumens of different lengths, the shorter lumen acting as blood intake lumen and the longer as a blood return lumen, each lumen having a beveled edge sloping outwardly and away from the needle which can be inserted percutaneously and which minimizes the possibility of mixing cleansed blood with blood entering the intake lumen.